Antenna-shortening device



W. DUBILIER.

ANTENNA SHORTENING DEVICE. APPLICATION FILED MAR.7.1919- RENEWED MAR. 5. 1921.

1,391,673. PatentedSept 27,1921.

2 SHEETS-SHEET I.

[0 :72 T'JLLWdnMm e W. DUBILIER.

ANTENNA SHORTENING DEVICE. I APPLICATION .FILED MAR. 1, 1919. RENEWED MAR. s. 1921.

Patented Sept. 27, 1921.

2 SHEETS-SHEET 2.

@012, auw k wgrmu UNITED STATES PATENT OFFICE.

WILLIAM DUBILIER, OF NEW YORK, N. Y., ASSIGNOR, IBY MESNE ASSIGNMENTS, TO D'UBILIER CONDENSER 00., INC., A CORPORATION OF NEW YORK,

Specification of Letters Patent.

anrnnna-snon'rnmne DEVICE.

Patented Sept. 27, 1921.

Application filed March- 7, 1919, Serial No. 281,181. Renewed March 5, 1921. Serial No. 449,745.

To all whom it may concern:

specifically 'mentioned in the descriptionhereinafter contained, in which is disclosed one embodiment of the invention; such embodlment however, 1s to be considered merely as illustrative of its principle.

In the drawings Figure 1 is an end elevation of a device made in accordance with the invention.

Figs. 2 and 3 are respectively a plan and side elevation of the same. I

Fig. 4 is a section on line 44 of Fig. 2 looking in the direction of the arrows, and

Fig. 5 is a diagrammatic showing of an antenna circuit containing the invention.

A suitable casing 1 carries the device as a whole, and is secured in position in any convenient manner. In the present instance, such casing is provided with a flange 2 at its base, said flange having suitable holes 2 for the reception of securing bolts.

The condenser is located within the interior of the casing, and preferably consists of a plurality of condenser sections 3, each consisting of a plurality of interleaved conducting plates and insulating sheets, all of said sections being coupled in series, as by suitable connectors 4 (Fig. 2) disposed on the sides of the sections. In the present instance, the condenser sections 3 are disposed substantially parallel to the side walls of easing 1, and spacing blocks 5, of insulating material, are employed to position the condenser within the casing. In order to insure that the condenser sections shall be firmly held in proper relation to each other, a clamping device is used to compress such sections tightly together. In the form disclosed, (Fig. 4) such clamping device consists of a metallic plate 6 bearing agalnst one of the spacing blocks 5, and a plurality of screws 7 which may be adjusted to prov1de the required amount of pressure on the plate 6, and thus compress said sections toward the o posite side wall of the casing.

A plura ity of connections 8 lead from d fferent sections of the condenser to terminal posts 9, carried by a cover 10 of the casmg to provide for variation in the amount of capacity of the condenser which is inserted in the circuit. In the present instance three of such adjustments are shown, although it will be obvious that a greater or less number may be used as desired. The form of terminal post disclosed is provided with a threaded metallic tube 10 which receives at its inner end a binding screw 11 which passes through the connection 8 and holds the latter in position.

A switch arm 12, having an operating handle 13, is rotatabl mounted upon a suitable post 14 carried by the cover 10, and a contact 15 carried by said switch arm passes over the terminal posts 9. It is advantageous however, that the contact 15 be not engageable with all of the terminal posts 9, but only with such terminal post as to insert the amount of capacity proper for the installation in which'the device is being used. This is accomplished in the present form by providing an interchangeable contact 16 which may be fixed upon any one of the terminal posts 9 by means of a screw 17 engaging in the outer endof the threaded tube 10, in position to contact with the contact 15 as the latter moves over the terminal posts. The remaining terminal posts 9 however, do not engage with the switch contact since the latter will pass freely over.

the screws 17 thereof, the latter serving merely as binding screws'in case circuit connections are desired to be made to the corresponding terminals.

With a construction of the above character, the condenser may be tested by the proper expert when installed, and the contact 16 mounted upon the corresponding terminal post, after which the switch contact 15 will not be open to the danger of being erroneously engaged with another terminal post to insert an incorrect amount of capacity into the circuit. A short circuiting contact 18 carried by a post 19, and extending to the adjacent post 9 is, however, always in position to be engaged by for instance through its flange 2.

the switch contact 15, so that the condenser may be readily cut out of circuit entirely whenever desired. Preferably the line connections are made respectively to the contact 18, and a terminal 20 carried by the post 14.

In the use of the apparatus, the casing 1 will ordinarily be made metallic, and provided witha suitable ground connection, Both the condenser sections, and the switch mechanism however, are completely insulated from the casing, and the grounded connection protects the apparatus from induced currents or other disturbances. Fig. 5 shows a convenient arrangement of the device in a radiating circuit including the antenna 21, the loadmg coil 22 and coupling coil 23, the casing 1 being grounded as above described.

While a specific form of the invention is described it is obvious that many changes may bemade without departing from its spirit as defined in the following claims.

I claim 1. An antenna shortening device comprising a casing, a condenser within said casing having a plurality of condenser sections connected in series, terminal posts carried by said casing, connections leading respectively from different sections of said condenser to said terminal posts, a switch arm movable with regard to said posts, and means whereby said arm may engage only one of said posts with a given setting of the condenser.

2. An antenna shortening device comprising a casing, a condenser within said 'casing, terminal posts carried by said casing, connections leading from different elements of said condenser to said terminal posts, a switch arm movable with regard to said posts, and an interchangeable contact adapted to be mounted on any of said posts in position to be engaged by said switch arm.

3. An antenna shortening device comprising a casing, a condenser within said casing, terminal posts carried by said casing, connections leading from different elements of said condenser to said terminal posts, a switch arm movable with regard to said posts and having a line connection thereon, means whereby said arm may engage only one of said posts with a given setting of the condenser, and a condenser short circuiting contact at all times engageable with said switch arm.

4. An electrical condenser comprising a metallic casing, a plurality of laminated condenser sectlons connected in series contained within said casing and disposed sub stantially parallel to side walls thereof, means for applying compression to said sections, a plurality of insulated terminals carried by the cover of said casing, and terminal connections leading from different condenser sections to said terminals.

5. An electrical condenser comprising a metallic casing, a plurality of laminated condenser sections connected in series contained within said casing and disposed sub stantially parallel to side walls thereof, means for applying compression to said sections, a plurality of insulated terminals carried by the cover of said casing, and terminal connections leading" from difierent condenser sections to said terminals, said sections being completely insulated from said casing.

6. An electrical condenser comprising a metallic casing, a plurality of laminated condenser sections connected in series contained within said casing and disposed substantially parallel to side walls thereof, means for applying compression to said sections, a plurality of insulated terminals carried by the cover of said casing, and terminal connections leading from different condenser sections to said terminals, and a switch arm mounted on said casing adapted to cooperate with said terminals.

7. An'electrical condenser comprising a metallic casing, a plurality of laminated condenser sections connected in series contained within said casing and disposed sub stantially parallel to side walls thereof, means for applying compression to said sections, a plurality of insulated terminals carried by the cover of said casing, and terminal connections leading from different condenser sections to said terminals, said compressionapplying means being disposed laterally of the condenser sections to leave open the space above the same.

In testimony that I claim the foregoing, I have hereunto set my hand this 21st day of February, 1919.

WILLIAM DUBII tan. 

